JP2006198564A - centrifuge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifuge realizing duplication of protection of an electric shock and reduction of a leak current by a relatively simple constitution regardless of existence of installed facilities without using any expensive transformer, a duplex insulation structure of a motor or a reinforced insulation structure. <P>SOLUTION: A switch 7 for making an electrical continuity or discontinuity is electrically connected into a driving electric power supply line L between a motor driving circuit 61a of a controller 61 and a motor winding 5c. The switch 7 makes a discontinuity when a door 3 is opened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure for ensuring electrical safety of a centrifuge.

  A centrifuge stores a rotor in which a sample to be separated is held through a tube or bottle in a rotor chamber (rotating chamber), and drives a motor or the like with the opening of the rotor chamber sealed by a door. By rotating the rotor at a high speed with an apparatus, the sample held in the rotor is separated, purified, and the like. The rotational speed of the rotor varies depending on the application, and it has a wide range of rotational speeds, from a relatively low speed with a maximum speed of several thousand revolutions (rpm) to a high speed with a maximum speed of about 150,000 revolutions (rpm). Product groups are generally available.

  A block diagram of a known centrifuge is shown in FIG. The centrifuge is a motor housing (housing) 5 containing a motor 5a that is a rotational drive source, a rotating shaft (shaft) 5b that is rotatably connected to the motor 5a, and a rotating shaft 5b fixed to the rotating shaft 5b. A rotor 1 that holds a sample to be stored, a rotor chamber 2 that houses the rotor 1 and has an opening 2a on the upper surface, a door 3 that can be opened and closed in the opening 2a of the rotor chamber 2, and a door 3 that opens and closes A door lock mechanism 4 for limiting, a door open / close detector 12 for detecting opening / closing of the door, and a control device 60 for controlling the motor 5a and the door lock mechanism 4 are provided, and the motor housing 5, the rotor chamber 2, and the door lock mechanism. 4 and the control device 60 are housed in a housing (frame) 10.

  In such a centrifugal separator, when the door 3 of the rotor chamber 2 is opened, the user may contact the rotating shaft 5b of the motor 5a or the rotor 1 that is electrically connected to the rotating shaft 5b. For this reason, generally an electric insulating layer is provided between the winding of the motor 5a and the rotating shaft 5b to prevent electric shock.

  In addition, even if such an insulating layer breaks down, no voltage is generated in the rotating shaft 5b, so that the housing 5 of the motor 5a that is electrically connected to the shaft 5b is electrically grounded by the ground connection line 8. By doing so, the electric shock prevention means is doubled. Usually, since the centrifuge housing 10 is connected to the ground connection line 9, the ground connection line 8 of the motor housing 5 is connected to a part of the centrifuge housing 10 located near the motor housing 5. Electrical connections are made. Note that the leakage current of the centrifuge is equal to or less than a predetermined leakage current that does not have a significant effect on the human body (for example, 3 or less) according to safety standards specified by JIS (Japanese Industrial Standards) or IEC (International Electrotechnical Commission). It is obliged to install a plurality of means for preventing electric shock for centrifuge members that are limited to .5 mA or less) and that may be contacted by the user. In the case where insulation is used as an electric shock prevention means, it is also defined that the insulation portion has a high withstand voltage (for example, 1300 V or more).

  However, depending on the usage state of the centrifuge, the user may use it in an environment without grounding equipment. In this case, since the above-mentioned electric shock prevention means by grounding cannot be adopted, as shown in FIG. 5, an insulation transformer 13 is used as another general electric shock prevention means to ensure safety. Yes. As another means for ensuring safety, there is a case in which a motor casing itself is double-insulated or reinforced with an insulating layer with respect to a winding.

  In addition, regarding the above prior art, a technique for preventing electric shock by applying an electrical insulating layer between the rotor winding and the rotating shaft of the motor, or a so-called double insulation in which the motor casing is also made of an insulator. This technique is disclosed in Patent Document 1 below. Further, a technique for preventing leakage current by an insulating transformer is disclosed in Patent Document 2 below. Further, in the centrifuge, a technique for ensuring safety when a user touches the rotor or the like by configuring the centrifuge rotor attached to the rotating shaft of the motor with an insulator is shown in Patent Document 3 below. Has been.

Japanese Utility Model Publication No. 60-20753 JP-A-9-187428 Japanese Patent Laid-Open No. 2001-87777

  However, the above-described structure using the insulating transformer 13 and the double-insulated or reinforced-insulated structure of the motor 5a are advantageous when the ground connection line 9 is not connected to the ground, but the structure causes an increase in cost. There's a problem. Moreover, in the technique described in Patent Document 3, there is a restriction that the processing material of the rotor is an insulator, and it is difficult to combine a commonly used metal material rotor with the centrifuge body.

  Furthermore, when adding an insulation transformer as described above, or performing double insulation or reinforced insulation of a motor, the leakage current via stray capacitance (stray capacitance) generated in these insulation parts is not limited to simply a plurality of means for preventing electric shock. Further measures are taken to limit (current flowing through the user's body when the user contacts) to a value equal to or less than the leakage current value defined in the safety standard.

  Therefore, the object of the present invention is to use the above-described high-cost insulation transformer, to use a double insulation structure or a reinforced insulation structure of the motor, and to take further measures to reduce the leakage current. It is another object of the present invention to provide a centrifugal separator which has a relatively simple configuration and which reduces leakage current and doubles electric shock prevention means.

  The above and other objects and novel features of the present invention will become more apparent from the following description of the present specification and the accompanying drawings.

  The inventor of the present application focused on the following characteristics of the centrifuge and constructed the invention. In other words, the centrifuge is usually configured to lock the door of the rotor chamber and prevent the door from being opened during operation, in order to ensure safety against an unexpected mechanical breakage during operation. Accordingly, since the centrifuge user cannot contact the rotating shaft or rotor of the motor being operated due to the door being closed, electric shock due to contact with the motor or rotor can be prevented. As a result, an electric shock prevention means is provided in the motor housing during operation. On the other hand, when the centrifuge is stopped, the user can open the door and contact the rotor, etc., so that the motor housing does not have double insulation or reinforced insulation structure to ensure electrical safety In this case, ground connection is required. However, since it is not necessary to rotate the motor during the stop, it is possible to provide an electric shock prevention means by disconnecting the motor drive circuit from the power source. Therefore, in both cases of operation and stop, a plurality of means for preventing electric shock can be realized together with the insulating structure provided between the winding of the motor and the rotating shaft.

  Of the inventions disclosed in the present application, the outline of typical ones will be described as follows.

  (1) According to the centrifuge of the present invention, a motor housing incorporating a motor that is a rotational drive source, a rotating shaft that is rotatably connected to the motor, and a sample that is fixed to the rotating shaft and separated. A rotor to be held; a rotor chamber that houses the rotor and has an opening on an upper surface; a door that is freely opened and closed at the opening of the rotor chamber; a door lock mechanism that restricts opening and closing of the door; A control device for controlling a motor; and a housing for housing the motor housing, the rotor chamber, the door lock mechanism, and the control device, and having an opening in the upper surface opening of the rotor chamber, In a centrifuge having a housing in which the door is openable and closable at an open portion, an electrically conductive or non-conductive opening / closing device connects a motor driving power for connecting the control device and the motor. A line electrically connected in, the door locking mechanism such that the non-conductive the switching device when not locking the door, and to control by the control device.

  (2) According to the centrifuge of the present invention described in (1) above, when the door lock mechanism does not lock the door, the opening / closing device is disabled.

  (3) According to the centrifuge of the present invention, a motor housing incorporating a motor that is a rotational drive source, a rotating shaft that is rotatably connected to the motor, and a sample that is fixed to the rotating shaft and separated. A rotor to be held, a rotor chamber that houses the rotor and has an opening on the upper surface, a door that can be opened and closed at the opening of the rotor chamber, and a door opening / closing detector that detects opening and closing of the door; A control device that controls the motor, a housing that houses the motor housing, the rotor chamber, and the control device, and has an opening in the upper surface opening of the rotor chamber, and the opening includes the opening In a centrifuge having a housing provided with a door that can be freely opened and closed, an electrically conducting or non-conducting opening / closing device is electrically connected to a motor drive power supply line that connects the control device and the motor. It is, to be non-conductive the switching device when the door is open, and to control by the control device.

  (4) According to the centrifuge of the present invention described in (3) above, when the door opening / closing detector detects the opening of the door, the opening / closing device is turned off. .

  (5) According to the centrifuge of the present invention described in the above (1) to (4), when the control device is not controlling the motor, the switchgear is made non-conductive. .

  (6) According to the centrifuge of the present invention described in the above (1) to (5), the switch is an electromagnetic switch.

  (7) According to the centrifuge of the present invention described in (1) to (6) above, the motor housing is electrically separated from the casing and is housed in the casing. To do.

  (8) According to the centrifuge of the present invention described in the above (1) to (7), the rotor is made of a metal material.

  According to the configuration of the present invention as described in the above (1), the electrically conductive or non-conductive switchgear is electrically connected in the motor drive power supply line connecting the control device and the motor, When the door of the centrifuge is opened and the user is in contact with the rotor or the motor rotation shaft, the switchgear is made non-conductive so that the electric shock prevention means is combined with the motor insulation. Therefore, it is possible to provide a centrifugal separator with a simple configuration and low cost, which does not require the addition of an insulation transformer and the double insulation or reinforced insulation of the motor as in the prior art. On the other hand, when the motor is operated, the switchgear is turned on, but the motor is locked by locking the door so that the centrifuge door is closed and the user cannot contact the rotor or the motor rotating shaft. It is possible to double the means for preventing electric shock in combination with the insulation.

  Further, according to the present invention as described in (6) above, since an electromagnetic switch is used as the switchgear, it is necessary between the switch terminals as a means for preventing electric shock when the electromagnetic switch is not conducting. A high withstand voltage (for example, 1300 V or more) can be easily obtained, and the stray capacitance (stray capacitance) between the open / close terminals can be reduced as compared with an open / close device using an electronic switch such as a transistor. It is also easy to suppress the leakage current generated when the user contacts the rotating shaft of the motor below a value determined by JIS or IEC.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted. Also, members having the same functions as those of the background art are given the same reference numerals as those of the background art.

  1 and 2 are block diagrams of a centrifuge according to an embodiment of the present invention. In particular, FIG. 1 shows that the switchgear 7 is in a non-conductive state, the motor 5a is stopped, and the rotor 1 rotates. FIG. 2 shows a state diagram when the opening / closing device 7 is in a conducting state, the motor 5a rotates, and the rotor 1 rotates. The centrifuge includes a housing (frame) 10, and is assembled and housed in a housing 5 made of a metal material containing a motor 5 a serving as a rotational drive source, and rotatable to the motor 5 a. A rotating shaft (shaft) 5b of a metal material connected to the rotor, a rotor 1 of a metal material (for example, aluminum alloy) that is fixed to the rotating shaft 5b and holds a sample to be separated, and the rotor 1 are accommodated and opened on the upper surface A rotor chamber 2 having a portion 2a, a door 3 provided in an opening 2a of the rotor chamber 2 formed in the housing 10, and a door lock mechanism 4 for restricting the opening and closing of the door 3, the door A door open / close detector 12 for detecting the opening / closing of the motor, an opening / closing device 7 electrically connected in the supply line L of the driving power of the motor 5a, a control device for controlling the motor 5a, the door lock mechanism 4, and the opening / closing device 7. 61 and be equipped That. The housing 10 is not electrically connected to the ground E. In the present invention, a ground connection line (corresponding to the connection line 8 in FIG. 6) for electrically connecting the motor housing 5 to the housing 10 is not provided.

  The motor 5a is composed of, for example, a three-phase induction motor activated by a 300V three-phase AC power source, and an insulating layer is formed between the winding of the motor 5a and the iron core, or on the outer peripheral surface of the rotating shaft 5b. . A more specific connection relationship between the motor 5a and the switchgear 7 is shown in FIG.

  As shown in FIG. 3, the control device 61 includes a motor drive circuit 61a, and the motor drive circuit 61a includes an inverter system. For example, the AC power supply 11 including a commercial AC power supply 100V or 200V (50/60 Hz) is an inverter. 61a converts to a three-phase AC power supply 300V (5 Hz to 2.6 kHz), and outputs a three-phase AC voltage to the lines L1, L2, and L3.

  The switchgear 7 has a characteristic of conducting (connecting) or non-conducting (cutting off) the line L according to a control signal applied to the control terminal CL. In a preferred embodiment, the switchgear 7 is composed of an electromagnetic switch (electromagnetic relay). The example shown in FIG. 3 is a case where a triple-link (three-contact type) electromagnetic switch 7 is used. The drive power supply lines L1, L2, and L3 are connected to the three contacts S1, S2, and S3 of the electromagnetic switch 7 serving as a switching device, and the three-phase AC power supply passes through these contacts and the three-phase winding of the induction motor 5a. 5c. Control of conduction (connection) or non-conduction (interruption) of each switch S1, S2, S3 of the electromagnetic switch 7 is controlled by a control signal of the control device 61 applied to the control terminal CL. FIG. 4 shows another configuration example in which an electromagnetic switch is used as the switchgear 7. The electromagnetic switch 7 in FIG. 4 is an example using three one-contact types (S1, S2, S3), and can be configured in the same manner as in FIG.

  Next, the operation according to the present invention will be described. As shown in FIG. 2, the opening / closing device (electromagnetic switch) 7 is controlled to be in a conductive state by the control device 61 when the door 3 is closed at the stage of operation of the centrifuge. When the door 3 is closed and the door opening / closing detector 12 detects the closed state of the door 3, or when the door is closed and the door is locked by the door lock mechanism 4, each of the electromagnetic switches 7 shown in FIG. The contacts S1, S2, and S3 are in a conductive state (connected state). Thereafter, the motor drive circuit 61a supplies a high three-phase AC power supply voltage (for example, 300V) to the motor winding 5c via the supply line L, and rotates the motor 5a. That is, the AC power supply 11 is boosted via the inverter 61a configured in the control device 61 and supplied to the winding 5c of the motor 5a. Therefore, during the operation of the motor 5a, there is only a single insulation applied to the motor 5a between the AC power source 11, the rotor 1 and the motor housing 5. However, during the operation of the motor 5a, the door 3 is closed and locked, the centrifuge user cannot touch the motor housing 5, the rotating shaft 5b of the motor 5a, or the rotor 1, while the motor housing 5 is electrically connected to the housing 10. Therefore, the second electric shock prevention means is installed.

  On the other hand, as shown in FIG. 1, when the operation of the centrifuge is stopped and the door 3 is opened, for example, after the operation of the motor 5a is stopped, the control device 61 releases the door lock mechanism 4 and the user 3 opens the door 3, the control device 61 receives the unlocking signal of the door lock mechanism 4 or the opening signal of the door opening / closing detector 12, and outputs the control signal to the control terminal CL, so that the opening / closing device shown in FIG. (Electric switch) The respective contacts S1, S2, and S3 of the electromagnetic switch 7 are made non-operating (shut off) to cut off the electrical connection with the drive power source for the winding 5c of the motor 5a. When the door 3 is opened, the user may come into contact with the rotating shaft 5b of the motor 5a or the rotor 1 that is electrically connected to the rotating shaft 5b. Since the electrical connection with the drive power supply to the motor winding 5c is interrupted by the device 7, the opening / closing device 7 functions as a second electric shock prevention means when the door 3 is opened.

  The advantage of using an electromagnetic switch as the switchgear 7 inserted according to the present invention is that the withstand voltage at both ends of the switchgear 7 when opened can be set to 1300 V or more, and the switchgear 7 is shut off. The stray capacitance (stray capacitance) Cs (see FIG. 3) between both ends of the non-conductive state can be reduced. In particular, when an electromagnetic switch is used, it is advantageous when performing a high withstand voltage test of a centrifuge, and since an electromagnetic switch has a small floating capacity Cs when cut off, it is used for a rotor or a rotating shaft of a rotor. This is advantageous in that the leakage current generated when a person touches can be reduced. When the switch device 7 may have a relatively low withstand voltage, an electronic switch including a semiconductor switch such as a transistor may be used in addition to the electromagnetic switch.

  The control of the opening / closing device 7 by the control device 61 may be executed when the door opening / closing detector 12 detects the opening / closing of the door 3, or when the door lock mechanism 4 detects the door lock or release thereof. May be. Further, when the control device 61 is not driving the motor 5a, the opening / closing device 7 may be controlled to be non-conductive.

  As shown in FIG. 2, when the centrifuge is used in an environment with a ground installation, the casing 10 of the centrifuge body may be connected to the ground E through the installation connection line 9. As will be apparent from the above description, according to the present invention, the switchgear is inserted into the motor drive power supply line, and the conduction / non-conduction control is controlled by the motor drive controller. Leakage current can be reduced and electric shock prevention means can be duplicated, so that there is no need to use a double insulation structure or a reinforced insulation structure for the motor core or rotating shaft, and the shape and material of the centrifuge rotor are limited. In addition, the intended purpose can be achieved with a relatively simple configuration.

  As mentioned above, although the invention made | formed by this inventor was demonstrated based on embodiment, this invention is not limited to the said embodiment, A various change is possible within the range which does not deviate from the summary.

The block diagram of the centrifuge which concerns on embodiment of this invention. The block diagram which shows the state which obstruct | occluded the door in the centrifuge of this invention shown in FIG. The principal part block diagram according to one structural example of the centrifuge of this invention shown in FIG. The principal part block diagram according to the other structural example of the centrifuge of this invention shown in FIG. The block diagram of the centrifuge which shows an example of a prior art. Configuration diagram of a centrifuge showing another example of the prior art

Explanation of symbols

1: Rotor 2: Rotor chamber 2a: Opening of rotor chamber 3: Door 4: Door lock mechanism 5: Motor housing (motor housing) 5a: Motor 5b: Rotating shaft (shaft) 5c: Motor winding (three phases) Winding)
60: Control device (conventional) 61: Control device (present invention)
61a: Motor drive circuit (including inverter) 7: Switchgear 8: Motor ground connection line 9: Housing ground connection line 10: Centrifuge body casing 11: AC power supply (commercial AC power supply) 12: Door open / close detector 13: Insulation transformer 14: Rotation detector CL: Control terminal E: Ground Cs: Stray capacitance (stray capacitance) L, L1, L2, L3: Drive power supply lines S, S1, S2, S3: Electromagnetic switch contacts

Claims (8)

A motor housing containing a motor as a rotational drive source; a rotary shaft rotatably connected to the motor; a rotor fixed to the rotary shaft and holding a sample to be separated; A rotor chamber having an opening; a door provided in the opening of the rotor chamber so as to be freely opened and closed; a door lock mechanism that restricts opening and closing of the door; a control device that controls the motor; the motor housing; A housing for housing the rotor chamber, the door lock mechanism, and the control device, wherein the housing has an opening at the upper surface opening of the rotor chamber, and the door is provided at the opening so as to be opened and closed. In a centrifuge having a body,
An opening / closing device that is electrically conductive or non-conductive is electrically connected to a line of a motor driving power source that connects the control device and the motor, and the opening / closing device is opened when the door lock mechanism does not lock the door. The centrifuge is controlled by the control device so as to make the device non-conductive.   The centrifuge according to claim 1, wherein when the door lock mechanism does not lock the door, the opening / closing device is disabled. A motor housing containing a motor as a rotational drive source; a rotary shaft rotatably connected to the motor; a rotor fixed to the rotary shaft and holding a sample to be separated; A rotor chamber having an opening, a door provided in the opening of the rotor chamber so as to be openable and closable, a door opening / closing detector for detecting opening and closing of the door, a control device for controlling the motor, the motor housing, A housing for housing the rotor chamber and the control device, the housing having an opening at the upper surface opening of the rotor chamber, and the housing having the door openable and closable at the opening. In the centrifuge
A switchgear that is electrically conductive or nonconductive is electrically connected in a line of a motor driving power source that connects the control device and the motor, and the switchgear is nonconductive when the door is open. As described above, the centrifuge is controlled by the control device.   The centrifuge according to claim 3, wherein when the door opening / closing detector detects opening of the door, the opening / closing device is turned off.   The centrifuge according to any one of claims 1 to 4, wherein when the controller is not controlling the motor, the switchgear is turned off.   The centrifuge according to any one of claims 1 to 5, wherein the switchgear is an electromagnetic switch.   The centrifuge according to any one of claims 1 to 6, wherein the motor housing is electrically separated from the housing and housed in the housing. The centrifuge according to any one of claims 1 to 7, wherein the rotor is made of a metal material.

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